1) Field of the Invention
The present invention relates to a process for preparing polycyclic compounds.
2) Description of the Related Art
Owing to recent developments in instrumental analyses and compound-isolating means, effective ingredients in crude drugs have been isolated and identified. Chemical syntheses of effective ingredients in crude drugs have been tried based on the above results. Crude drugs, however, include many compounds whose chemical syntheses are extremely difficult because of the presence of a complex ring system. Such difficulties still remain as an obstacle for the establishment of chemical processes for the synthesis of such crude drug ingredients in more than a few instances.
For example, some compounds containing a dibenzocyclooctane or benzocyclooctene ring represented by the following formula: ##STR3## have been known as effective ingredients of crude drugs. It is, however, difficult to synthesize the above ring system in any manner known to date. It has therefore been regarded difficult to industrially prepare these ingredients by a chemical synthesis process.
Determination of an effective ingredient of a crude drug makes it possible to administer only the effective ingredient in order to prevent side effects and reduce the dosage of the crude drug. This is certainly considered preferable. Extraction of only an effective ingredient from a crude drug is accompanied with the drawbacks that an extra complicated step is required to remove other ingredients and the yield is poor. Further, the amount of production of the crude drug source itself is limited, resulting in problems in both economy and resource.